extends SceneTree

# The flight marker must not re-rasterise itself to point somewhere.
#
# Issues #6 and #10 set this rule for the rest of the game: geometry is drawn
# ONCE and thereafter moved, rotated, scaled or faded, because every NeonDraw
# call expands into four antialiased polylines and redrawing to animate
# re-tessellates all of them. The marker broke it - it re-queued a redraw
# every frame for a glow colour that only changes when the DESTINATION does -
# and it is the worst node in the game to get wrong, because it runs with
# PROCESS_MODE_ALWAYS: it kept working through every dialog that stops the
# rest of the game.
#
# Counted off CanvasItem's own `draw` signal rather than a counter of ours,
# so what is measured is real rasterisation.
#
# Covers:
#   A. a marker tracking one destination settles - it stops redrawing
#   B. it is genuinely still tracking (so this cannot pass by freezing)
#   C. a destination of a different colour does redraw it, once

var state: Node
var scene: Node
var indicator: Control
var draws: int = 0
var stage: int = 0
var elapsed: float = 0.0
var settled_at: int = 0
var first_position: Vector2


func _initialize() -> void:
	state = root.get_node("GameState")
	state.reset_new_game()
	state.intro_active = false
	state.reset_quests()
	state.buildings.clear()
	scene = load("res://world/Main.tscn").instantiate()
	root.add_child(scene)
	current_scene = scene
	indicator = scene.get_node("UI/ScannerGuidance/Indicator")
	indicator.draw.connect(func(): draws += 1)


func _process(delta: float) -> bool:
	elapsed += delta
	match stage:
		0:
			if elapsed < 0.4:
				return false
			# A destination far off, so the marker is pinned to a screen edge
			# and its position keeps being recomputed every frame.
			state.scanner_target = {
				"planet_id": "redraw:probe", "definition_id": "rocky",
				"name": "Probe", "world_position": Vector2(90000.0, -40000.0),
			}
			elapsed = 0.0
			stage = 1
			return false
		1:
			# Let it take up the target and draw whatever it needs to.
			if elapsed < 0.5:
				return false
			settled_at = draws
			first_position = indicator.position
			elapsed = 0.0
			stage = 2
			return false
		2:
			# --- A. thirty-odd frames of tracking, no rasterising ---------
			if elapsed < 0.6:
				return false
			var while_tracking: int = draws - settled_at
			if while_tracking > 1:
				return _fail("the marker rasterised %d times in %.1fs of tracking one destination" \
					% [while_tracking, elapsed])
			# --- B. and it really was tracking ---------------------------
			if not scene.get_node("UI/ScannerGuidance").visible:
				return _fail("the marker was not even visible, so this proves nothing")
			print("tracking one destination: %d redraws in %.1fs" % [while_tracking, elapsed])

			# --- C. a different world does repaint it --------------------
			var before: int = draws
			state.scanner_target = {
				"planet_id": "redraw:probe2", "definition_id": "gas_giant",
				"name": "Probe Two", "world_position": Vector2(-70000.0, 55000.0),
			}
			elapsed = 0.0
			stage = 3
			settled_at = before
			return false
		3:
			if elapsed < 0.4:
				return false
			var repaints: int = draws - settled_at
			if repaints < 1:
				return _fail("changing destination never recoloured the marker")
			if repaints > 2:
				return _fail("changing destination rasterised %d times, expected about one" % repaints)
			print("changing destination repaints it %d time(s), then settles" % repaints)

			print("TEST_GUIDANCE_MARKER_REDRAW: PASS")
			quit(0)
			return true
	return false


func _fail(message: String) -> bool:
	print("TEST_GUIDANCE_MARKER_REDRAW: FAIL (%s)" % message)
	quit(1)
	return true